bash sed 加号不起作用
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/22099623/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
sed plus sign doesn't work
提问by J33nn
I'm trying to replace /./or /././or /./././to /only in bash script. I've managed to create regex for sed but it doesn't work.
我试图取代/./或/././或/./././以/仅在bash脚本。我已经设法为 sed 创建正则表达式，但它不起作用。
variable="something/./././"
variable=$(echo $variable | sed "s/\/(\.\/)+/\//g")
echo $variable # this should output "something/"
When I tried to replace only /./substring it worked with regex in sed \/\.\/. Does sed regex requires more flags to use multiplication of substring with +or *?
当我尝试仅替换/./子字符串时，它与 sed 中的正则表达式一起使用\/\.\/。sed regex 是否需要更多标志才能使用子字符串与+或 的乘法*？
回答by falsetru
Use -roption to make sedto use extended regular expression:
使用-r选项使sed使用扩展正则表达式：
$ variable="something/./././"
$ echo $variable | sed -r "s/\/(\.\/)+/\//g"
something/
回答by Scrutinizer
Any sed:
任何 sed：
sed 's|/\(\./\)\{1,\}|/|g'
But a +or \{1,\}would not even be required in this case, a *would do nicely, so
但是在这种情况下甚至不需要a +or \{1,\}， a*会很好，所以
sed 's|/\(\./\)*|/|g'
should suffice
应该足够了
回答by jaypal singh
Two things to make it simple:
两件事使它变得简单：
$ variable="something/./././"
$ sed -r 's#(\./){1,}##' <<< "$variable"
something/
- Use
{1,}to indicate one or more patterns. You won't needgwith this. - Use different delimiterers
#in above case to make it readable +is ERE so you need to enable-Eor-roption to use it
- 使用
{1,}以表示一个或多个模式。你不需要g这个。 #在上述情况下使用不同的分隔符使其可读+是 ERE 所以你需要启用-E或-r选择使用它
回答by Mark Setchell
You can also do this with bash's built-in parameter substitution. This doesn't require sed, which doesn't accept -ron a Mac under OS X:
您也可以使用 bash 的内置参数替换来做到这一点。这不需要sed，它-r在 OS X 下的 Mac上不接受：
variable="something/./././"
a=${variable/\/*/}/ # Remove slash and everything after it, then re-apply slash afterwards
echo $a
something/
See herefor explanation and other examples.
有关说明和其他示例，请参见此处。
